Goals
Compare and contrast Git and GitHub
List use cases for GitHub
Get started with GitHub!
What is Github?
GitHub is a web-based Git repository hosting service.
Simply put, it is a tool that enables collaboration by hosting shared Git repositories that teams of developers can all contribute to.
While GitHub uses Git, the functionality it provides is VERY different from Git so make sure you understand that Git and GitHub are not the same thing.
In short, Git is a Version Control System. GitHub is an online platform for hosting and sharing code, text files and even more complex file formats.
Why use GitHub?
It provides a great way for you to store your code in a remote location
It’s a fantastic way to collaborate with other developers both privately and publicly
Many large open source projects are hosted on GitHub, which makes it very easy to examine the code both on GitHub and locally
In the next couple of chapters, we will learn how to move code from our local repository to a remote repository on GitHub using the push command
Who uses GitHub?
Here are some projects you may have heard of that are hosted there:
Node.js - https://github.com/nodejs/node
Angular - https://github.com/angular/angular
Ruby on Rails - https://github.com/rails/rails
Twitter Bootstrap - https://github.com/twbs/bootstrap
jQuery - https://github.com/jquery/jquery
Homebrew - https://github.com/Homebrew/brew
Getting started with GitHub
If you don’t have an account with GitHub yet, head to https://github.com/ and create an account
Be sure to use whatever email address is in your .gitconfig for your email address when you sign up with GitHub.
If you’d rather sign up with a different email address, change your .gitconfig accordingly.
You’ll run into some minor annoyances if there’s a mismatch between the email address in your GitHub profile and the email address in your .gitconfig.
Creating Remote Repositories on GitHub
Navigate to https://www.github.com/new
After naming and creating a new repository click create repository
Follow the second block of instructions for pushing an existing repository from the command line
What are we doing here?
Adding a remote
Calling it “origin”
What’s a remote?
It’s a nickname for a URL where your repository lives!
Instead of typing/remembering the entire URL, we give it a nickname
By default this nickname is origin
git remote add NAME_OF_REMOTE URL_FOR_REPOSITORY
NAME_OF_REMOTE: origin
URL_FOR_REPOSITORY: https://github.com/YOUR_USERNAME/YOUR_REPO.git
git remote add
This command tells our local repository about a remote repository located somewhere.
The location of our remote repository is https://github.com/YOUR_USERNAME/YOUR_REPO.git.
git push origin
Now if we want to send our code to GitHub we could type in
git push https://github.com/YOUR_USERNAME/YOUR_REPO.git master
but typing that whole URL is quite a pain.
Instead, we give the URL a nickname (also called an alias) - “origin”
Once the alias is set up we can simply type
git push origin master
This will send the code from our master branch to this remote repository.
To see where your remotes are pointing to locally, type git remote -v.
This will display both the alias and the remote url
If you need to remove a remote you can use git remote rm NAME_OF_REMOTE
Pushing Your Code
The command we use is git push NAME_OF_REMOTE NAME_OF_BRANCH
Setting the upstream
git push -u origin master
Shell
Now we can send our code from a local repository to our remote repository (which we aliased to origin in the previous command).
The -u flag allows us in the future to only have to type git push instead of git push origin master.
Pushing code up to GitHub
Now when you type in git push, you will be prompted to enter your username and password for GitHub. While that is fine once or twice, it becomes quite a nuisance if you are pushing or pulling (retrieving code) frequently.
It would be nice if we could establish some trust between our computer and GitHub so that when we run git push or git pull, GitHub does not need to authenticate us. To do that we are going to create an SSH key.
Practice
Generate some code files on your machine and set up a local repository using git init .
Create a remote repository on github to push your code to
Use git remote add to point the local repo to the remote repo and set up an alias (origin)
Add and commit your code to generate a master branch
Push your code to the remote repo using git push origin master
Go back to github and refresh the page, you should be able to see your code
Change some code and add and commit a second time
This time set the upstream branch
You should now be able to push your code with git push in the future
More Practice
Create another remote repo on github
Point the existing local repo to the new remote repo and set up an alias
We have shown how to view, add and remove the remote
Research git remote set-url if you are curious how update the remote with one line of code
Push your code to the second remote repo
Examine both the repos on Github that you have pushed code to
Notice the new repo has all of the commit history
The commit history belongs to the local git repo
The remote github repo just provides a interface for people to share code